The subject matter disclosed herein relates generally to apparatus and methods for diagnostic medical imaging, such as, for example, positron emission tomography (PET) imaging.
PET is a medical imaging technique that provides functional information regarding physiological processes of an object (e.g., human patient) being imaged. Radiopharmaceuticals may be administered to a patient, resulting in emitted positrons, which undergo annihilation with electrons, generating photons that travel in opposite directions. The photons may be detected, with each event stored in an array referred to as a sinogram. The measured sinogram data may be used to reconstruct a three-dimensional distribution corresponding to the radiopharmaceutical as part of an image reconstruction.
The image matrix used in medical imaging such as PET may have anisotropic voxels, or voxels having non-uniform size in at least one dimension with respect to the other dimensions. During an iterative reconstruction, voxels having a longer length in one dimension may result in over-smoothing in that direction and/or step artifacts, for example.